Modern wind turbines, also called wind motors or wind engines, are employed to produce electricity, They are often very large structures with blades measuring up to 60 meters or more, and which are made from fibre-reinforced polymer shells.
Icing of wind turbine blades is a widespread problem with several negative results. Icing can change the profile of the blade and thus the aerodynamic properties of the blade, impeding efficiency. Furthermore, non-uniform icing can cause severe asymmetric stress to the wind turbine structure, which can result in the operation having to be interrupted.
DE 196 21 485 discloses a wind turbine blade, the inside of which is heated by means of warm air with a view to deicing.
WO 98/53200 discloses a wind turbine blade, which can be defrosted by means of heating elements Including conductive fibres.
U.S. Pat. No. 4,060,212 discloses the method of deicing rotor blades on helicopters by means of microwaves.
Background art also discloses the method of preventing icing on plane wings by spraying the plane wings with a defrosting agent immediately prior to take-off.
During recent years, wind turbines have been erected offshore, as there the velocity of wind is great due to the absence of leeward. Also, by placing these very tall wind turbines with blades of up to 60 m or more offshore, nuisances from placing such wind turbines in areas of natural beauty are avoided.
U.S. Pat. No. 6,520,737 B1 discloses an offshore wind turbine with a pump able to pump sea water up for cooling purposes.